Ink, ink cartridge and ink jet recording method

ABSTRACT

The invention provides an ink containing a coloring material and a water-soluble organic solvent, wherein the coloring material is a compound represented by the following general formula (1), and the water-soluble organic solvent includes an alkanediol having 4 to 6 carbon atoms: 
     
       
         
         
             
             
         
       
     
     wherein rings A, B, C and D each indicated by a broken line are, independently of one another, a benzene ring or a nitrogen-containing heteroaromatic ring, the number of the nitrogen-containing heteroaromatic ring is more than 0.0 and 3.0 or less, the remainder is the benzene ring, R 1  is an alkyl group, R 2  is an alkylene group, X is an anilino group having one or more sulfonic groups, m is more than 0.0 and less than 3.9, n is 0.1 or more and less than 4.0, and the sum of m and n is 1.0 or more and less than 4.0.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ink, an ink cartridge and an ink jetrecording method.

2. Description of the Related Art

An ink jet recording method is such a recording method that minutedroplets of an ink are applied to a recording medium such as plain paperto form an image, and is rapidly spread owing to low price of anapparatus itself and improvement of recording speed. In general, arecorded article obtained by the ink jet recording method is low infastness properties of an image thereof compared with a silver saltphotograph. In particular, when the recorded article is exposed tolight, temperature, heat or environmental gas present in air, such as anozone gas for a long period of time, there is a problem that a coloringmaterial of the recorded article is deteriorated to easily cause changein color tone or fading of the image.

Since the change in color tone or fading of the image is causedespecially by a cyan ink low in ozone resistance among respective inksof cyan, yellow and magenta as a main factor, there are a great numberof proposals for improving the ozone resistance of the cyan ink. Forexample, there are proposals for improving the ozone resistance of animage by devising the structure of a phthalocyanine compound often usedas a coloring material of the cyan ink (see International PublicationNo. 2004/087815 and International Publication No. 2007/091631).

As another problem in the cyan ink using the phthalocyanine compound,metallic luster, what is called a bronzing phenomenon, caused by highaggregation property of the phthalocyanine compound is mentioned. Whenthe bronzing phenomenon is caused, the optical reflecting properties ofthe image are changed, and so the color developability and hue thereoflook markedly poor to cause lowering of image quality. The bronzingphenomenon is considered to be caused by aggregation of the coloringmaterial on the surface of a recording medium or in the neighborhoodthereof due to the high aggregation property of the coloring materialand lowering of permeability of an ink into the recording medium whenthe ink is applied to the recording medium. In order to inhibit theoccurrence of the bronzing phenomenon, it has been proposed to add apolyhydric alcohol or an ether compound to an ink containing, forexample, a copper phthalocyanine compound (see Japanese PatentApplication Laid-Open No. 2005-350565).

SUMMARY OF THE INVENTION

The present inventors have carried out an investigation mainly as to theproposals described in International Publication No. 2004/087815,International Publication No. 2007/091631 and Japanese PatentApplication Laid-Open No. 2005-350565 for the purpose of providing acyan ink improved in both ozone resistance and bronzing resistance andcapable of recording an image in which these properties are achieved atthe same time. However, all the inks described in InternationalPublication No. 2004/087815, International Publication No. 2007/091631and Japanese Patent Application Laid-Open No. 2005-350565 have not ledto recording of an image excellent in ozone resistance and bronzingresistance. For example, when the phthalocyanine compound described inInternational Publication No. 2004/087815 or International PublicationNo. 2007/091631 has been used, the bronzing resistance of an imagerecorded has fallen within an allowable range, but the ozone resistancethereof has been insufficient. Even when the ink described in JapanesePatent Application Laid-Open No. 2005-350565 has been used, the ozoneresistance of an image recorded has not been said to be sufficient. Inaddition, it has been found that in this case, the sticking resistanceof the ink becomes insufficient according to the kind of the polyhydricalcohol.

Accordingly, it is an object of the present invention to provide an inkcapable of recording an image excellent in ozone resistance and bronzingresistance and excellent in sticking resistance. Another object of thepresent invention is to provide an ink cartridge and an ink jetrecording method using the above-described ink.

The above objects can be achieved by the present invention describedbelow. That is, according to the present invention, there is provided anink comprising a coloring material and a water-soluble organic solvent,wherein the coloring material contains a compound represented by thefollowing general formula (1), and the water-soluble organic solventcontains an alkanediol having 4 to 6 carbon atoms.

wherein rings A, B, C and D each indicated by a broken line are,independently of one another, a benzene ring or a nitrogen-containingheteroaromatic ring, the number of the nitrogen-containingheteroaromatic ring is more than 0.0 and 3.0 or less, the remainder isthe benzene ring, R₁ is an alkyl group, R₂ is an alkylene group, X is ananilino group having one or more sulfonic groups, with the proviso thatX may have one or more substituents selected from the group consistingof a carboxy group, a phosphoric group, a hydroxy group, an alkoxygroup, an alkylcarbonylamino group, a ureido group, a nitro group and ahalogen atom, m is more than 0.0 and less than 3.9, n is 0.1 or more andless than 4.0, and the sum of m and n is 1.0 or more and less than 4.0.

According to the present invention, there can be provided an ink capableof recording an image excellent in ozone resistance and bronzingresistance and excellent in sticking resistance. In addition, accordingto the present invention, there can also be provided an ink cartridgeand an ink jet recording method using this ink.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view schematically illustrating an ink cartridgeaccording to an embodiment of the present invention.

FIGS. 2A and 2B schematically illustrate an exemplary ink jet recordingapparatus used in an ink jet recording method according to the presentinvention, in which FIG. 2A is a perspective view illustrating aprincipal part of the ink jet recording apparatus, and FIG. 2B is aperspective view illustrating a head cartridge.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings. Incidentally, whena compound is a salt, the salt present in an ink in a state of beingdissociated into ions. In the present invention, however, this isreferred to as “containing a salt” for the sake of convenience. Althougha compound represented by the general formula (1) is a mixture asdescribed below, the compound is represented by the general formula (1)as a structure of a typical example of the mixture for the sake ofconvenience. The numbers of the respective rings and substituents areindicated as average values thereof. This coloring material is awater-soluble dye exhibiting a cyan color and may be favorably used as acoloring material for a cyan ink or for color adjustment of anothercolor ink. Incidentally, in the present specification, the compoundrepresented by the general formula (1) may be simply described as“coloring material” collectively in some cases for the sake ofconvenience.

The ink according to the present invention contains the compoundrepresented by the general formula (1) as a coloring material and awater-soluble organic solvent including an alkanediol having 4 to 6carbon atoms. With the ink according to the present invention adoptingsuch composition, the coloring material is caused to penetrate into adeep portion of a recording medium by utilizing the permeability of thealkanediol upon recording of an image, whereby the coloring material canbe uniformly distributed in the recording medium and an ink receivinglayer thereof. In addition, as described below, the compound representedby the general formula (1) is excellent in the resistance to an ozonegas owing to its high aggregation property. Therefore, the use of theink according to the present invention enables recording an imageexcellent in ozone resistance and bronzing resistance compared with thecase where a conventional ink is used.

The present inventors have considered that it is important to enhancethe aggregation property of a coloring material for improving the ozoneresistance of an image recorded with a cyan ink and carried out variousinvestigations as to the structure of the coloring material. As aresult, it has been found that since the compound represented by thegeneral formula (1) is high in aggregation property, the ozoneresistance of an image recorded with an ink containing this compound asa coloring material is improved. In addition, the present inventors haveevaluated the bronzing resistance of an image recorded with the inkcontaining the compound represented by the general formula (1) as thecoloring material. As a result, it has been found that the bronzingresistance of the image recorded is not at a sufficient level. Thebronzing phenomenon is a phenomenon caused by the situation that acoloring material is topically present on the surface of a recordingmedium and in the neighborhood thereof. It is thus considered that thebronzing resistance of the image recorded with the ink containing, asthe coloring material, the compound represented by the general formula(1) which is high in aggregation property has become insufficient.

Thus, in order to solve the problem that the bronzing resistance of theimage recorded with the ink containing the compound represented by thegeneral formula (1) as the coloring material is lowered, the presentinventors have carried out a further investigation. As a result, it hasbeen found that an alkanediol having 4 to 6 carbon atoms is caused to becontained together with the compound represented by the general formula(1), whereby an image improved in both ozone resistance and bronzingresistance can be recorded. The present inventors presume the reason whyboth ozone resistance and bronzing resistance of the image recorded areimproved to be as follows.

Since the alkanediol is a compound with two hydroxy groups bonded to analkyl chain that is a main chain, it exhibits behavior like asurfactant. However, the surface tension of the resulting ink is notlowered in excess. Therefore, the alkanediol is caused to be containedin the ink, whereby proper permeability and leveling property can beimparted to the ink. In particular, when the compound represented by thegeneral formula (1) and the alkanediol having 4 to 6 carbon atoms arecaused to be contained in the ink, a balance between permeability andleveling property in the ink is optimized, and the sticking resistanceof the ink is not impaired. Therefore, the compound represented by thegeneral formula (1) that is a coloring material easily penetrates into arecording medium in a state of being uniformly distributed in therecording medium and an ink receiving layer thereof. As a result, it isconsidered that the ozone resistance and bronzing resistance of theimage are improved. Incidentally, the permeability of the ink can beimproved by using a surfactant. However, the surface tension or stickingresistance of the ink may be lowered in excess in some cases. It is thusnecessary to use the alkanediol having 4 to 6 carbon atoms.

Ink

The respective components constituting the ink according to the presentinvention will hereinafter be described in detail.

Coloring Material

The ink according to the present invention is required to contain, as acoloring material, a compound represented by the following generalformula (1):

wherein rings A, B, C and D each indicated by a broken line are,independently of one another, a benzene ring or a nitrogen-containingheteroaromatic ring, the number of the nitrogen-containingheteroaromatic ring is more than 0.0 and 3.0 or less, the remainder isthe benzene ring, R₁ is an alkyl group, R₂ is an alkylene group, X is ananilino group having one or more sulfonic groups, with the proviso thatX may have one or more substituents selected from the group consistingof a carboxy group, a phosphoric group, a hydroxy group, an alkoxygroup, an alkylcarbonylamino group, a ureido group, a nitro group and ahalogen atom, m is more than 0.0 and less than 3.9, n is 0.1 or more andless than 4.0, and the sum of m and n is 1.0 or more and less than 4.0.

In the general formula (1), the number of the nitrogen atom contained asa ring forming atom in the nitrogen-containing heteroaromatic ring ofthe rings A, B, C and D each indicated by the broken line is generally 1or 2, preferably 1. As specific examples of the nitrogen-containingheteroaromatic ring, pyridine containing one nitrogen atom as well aspyrazine, pyridazine and pyrimidine containing two nitrogen atoms may bementioned. Among these, the pyridine ring is particularly favorable. Noparticular limitation is imposed on a fused ring position of thenitrogen-containing heteroaromatic ring with the porphyrazine ring. Forexample, when the nitrogen-containing heteroaromatic ring of the ringsA, B, C and D is a pyridine ring and the position of the nitrogen atomis regarded as position 1, a fused ring is favorably formed at positions2 and 3 or positions 3 and 4, particularly favorably at positions 3 and4. The number of the nitrogen-containing heteroaromatic ring of therings A, B, C and D is more than 0.0 and 3.0 or less, favorably 0.2 ormore and 2.0 or less, more favorably 0.5 or more and 1.7 or less,particularly favorably 0.7 or more and 1.5 or less. The remainder of therings A, B, C and D is the benzene ring. The number of the benzene ringof the rings A, B, C and D is 1.0 or more and less than 4.0, favorably2.0 or more and 3.8 or less, more favorably 2.3 or more and 3.5 or less,particularly favorably 2.5 or more and 3.3 or less.

Incidentally, in the present specification, the number of thenitrogen-containing heteroaromatic ring is described by rounding off toone decimal place unless expressly noted. However, when the number ofthe pyridine ring is 1.35, the number of the benzene ring is 2.65, andboth are rounded off to one decimal place, the former is 1.4, the latteris 2.7, and the total of both becomes larger than 4.0 of the total ofthe rings. In such a case, the number of the nitrogen-containingheteroaromatic ring is omitted below two decimal places for the sake ofconvenience, only the number of the benzene ring is rounded off, andthus the former and the latter are described as 1.3 and 2.7,respectively. In addition, m and n in the general formula (1) are alsodescribed by rounding off to one decimal place in principle. However,when the total of both of them exceeds the theoretical value, m isomitted below two decimal places, and only n is rounded off to expressthem.

As the alkyl group indicated by R₁ in the general formula (1) includes alinear, branched or cyclic alkyl group. Among these, a linear orbranched alkyl group is favorable, and a linear alkyl group is morefavorable. The number of carbon atoms in the alkyl group is generally 1or more and 6 or less, favorably 1 or more and 4 or less, more favorably1 or more and 3 or less. As specific examples of the alkyl group, linearalkyl groups such as methyl, ethyl, n-propyl, n-butyl and n-pentyl,n-hexyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl,t-butyl, isopentyl and isohexyl; and cyclic alkyl groups such ascyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl may be mentioned.Among these, a methyl, ethyl or isopropyl group is favorable, a methylor ethyl group is more favorable, and a methyl group is particularlyfavorable.

The alkylene group indicated by R₂ in the general formula (1) includes alinear, branched or cyclic alkylene group. Among these, a linear orbranched alkylene group is favorable, and a linear alkylene group ismore favorable. The number of carbon atoms in the alkylene group isgenerally 2 or more and 12 or less, favorably 2 or more and or less,more favorably 2 or more and 4 or less, particularly favorably 2 or moreand 3 or less. As specific examples of the alkylene group, linearalkylene groups such as ethylene, propylene, butylene, pentylene,hexylene, heptylene, octylene, nonylene, decylene, undecylene anddodecylene; branched alkylene groups such as 2-methylethylene; andcyclic alkylene groups such as cyclopropylenediyl, 1,2- or1,3-cyclopentylenediyl and 1,2-, 1,3- or 1,4-cyclohexylenediyl may bementioned. Among these, a methylene, ethylene or propylene group isfavorable, an ethylene or propylene group is more favorable, and anethylene group is particularly favorable.

The anilino group having one or more sulfonic groups, indicated by X inthe general formula (1) includes an anilino group having generally oneto three, favorably one or two, more favorably two sulfonic groups. Asspecific examples of the anilino group having one or more sulfonicgroups, anilino groups having one sulfonic group, such as2-sulfoanilino, 3-sulfoanilino and 4-sulfoanilino; anilino groups havingtwo sulfonic groups, such as 2,3-disulfoanilino, 2,4-disulfoanilino,2,5-disulfoanilino, 3,4-disulfoanilino and 3,5-disulfoanilino; andanilino groups having three sulfonic groups, such as2,3,4-trisulfoanilino, 2,3,5-trisulfoanilino, 2,3,6-trisulfoanilino and3,4,5-trisulfoanilino may be mentioned. Among these, a2,5-disulfoanilino group is particularly favorable.

When the anilino group having one or more sulfonic groups, indicated byX in the general formula (1) further has another substituent than thesulfonic group, the number of another substituent than the sulfonicgroup is generally 1 or 2, favorably 1. The kind of the substituent maybe either single or plural. As examples of another substituent than thesulfonic group, a carboxy group, a phosphoric group, a hydroxy group, analkoxy group, an alkylcarbonylamino group, an ureido group, a nitrogroup and a halogen atom may be mentioned. Specific examples of anothersubstituent than the sulfonic group that the anilino group having one ormore sulfonic groups, indicated by X may have are mentioned below.

The alkoxy group includes a linear, branched or cyclic alkoxy group. Alinear or branched alkoxy group is favorable, and a linear alkoxy groupis more favorable. The number of carbon atoms in the alkoxy group isgenerally 1 or more and 6 or less, favorably 1 or more and 4 or less,more favorably 1 or more and 3 or less. As specific examples of thealkoxy group, linear alkoxy groups such as methoxy, ethoxy, n-propoxy,n-butoxy, n-pentoxy and n-hexyloxy; branched alkoxy groups such asisopropoxy, isobutoxy, sec-butoxy, t-butoxy, isopentyloxy andisohexyloxy; and cyclic alkoxy groups such as cyclopropoxy, cyclopentoxyand cyclohexyloxy may be mentioned. Among these, a methoxy, ethoxy orisopropoxy is favorable, and a methoxy group is more favorable.

The alkylcarbonylamino group includes a linear or branchedalkylcarbonylamino group, and a linear alkylcarbonylamino group isfavorable. The number of carbon atoms in an alkyl portion of thisalkylcarbonylamino group is generally 1 or more and 6 or less, favorably1 or more and 4 or less, more favorably 1 or more and 3 or less. Asspecific examples of the alkylcarbonylamino group, linearalkylcarbonylamino groups such as methylcarbonylamino(acetylamino),ethylcarbonylamino, n-propylcarbonylamino and n-butylcarbonylamino; andbranched alkylcarbonylamino groups such as isopropylcarbonylamino may bementioned. Among these, an acetylamino group is favorable.

The ureido group includes an unsubstituted ureido group, an alkylureidogroup or an arylureido group. As specific examples of the alkylureidoand arylureido group, alkylureido groups such as methylureido,ethylureido, N,N-dimethylureido and N,N-dibutylureido; and arylureidogroups such as phenylureido may be mentioned. Among these, anunsubstituted ureido group is favorable.

The halogen atom includes a fluorine atom, a chlorine atom, a bromineatom or an iodine atom. Among these, a chlorine atom is favorable.

m, n and the sum of m and n in the general formula (1) are each anaverage value. m indicates the substitution number of the unsubstitutedsulfamoyl group and is more than 0.0 and less than 3.9. n indicates thesubstitution number of the substituted sulfamoyl group and is 0.1 ormore and less than 4.0. The sum of m and n is 1.0 or more and less than4.0. When the number of the nitrogen-containing heteroaromatic ring ofthe rings A, B, C and D is 0.2 or more and 2.0 or less and the number ofthe benzene ring is 2.0 or more and 3.8 or less, it is favorable that mis 1.8 or more and 3.6 or less, n is 0.2 or more and 2.0 or less, andthe sum of m and n is 2.0 or more and 3.8 or less. When the number ofthe nitrogen-containing heteroaromatic ring of the rings A, B, C and Dis 0.3 or more and 1.5 or less and the number of the benzene ring is 2.5or more and 3.7 or less, it is favorable that m is 2.2 or more and 3.0or less, n is 0.3 or more and 1.5 or less, and the sum of m and n is 2.5or more and 3.7 or less. In addition, when the number of thenitrogen-containing heteroaromatic ring of the rings A, B, C and D is0.5 or more and 1.2 or less and the number of the benzene ring is 2.8 ormore and 3.5 or less, it is favorable that m is 2.1 or more and 3.1 orless, n is 0.4 or more and 1.4 or less, and the sum of m and n is 2.8 ormore and 3.5 or less.

Since the aggregation property of the compound represented by thegeneral formula (1) tends to become high as the value m increases, theozone resistance of an image recorded tends to be improved, while abronzing phenomenon tends to easily occur. Thus, it is favorable thatthe values m and n are suitably adjusted while taking the ozoneresistance and bronzing resistance of the image recorded intoconsideration to select a well-balanced ratio between them.Incidentally, the unsubstituted sulfamoyl group and the substitutedsulfamoyl group whose substitution numbers are indicated by m and n,respectively, are each a group introduced into the benzene ring of therings A, B, C and D. That is, both the unsubstituted sulfamoyl group andthe substituted sulfamoyl group are not introduced into thenitrogen-containing heteroaromatic ring of the rings A, B, C and D.

The compound represented by the general formula (1) may be a free acidform (H form) or may form a salt (salt form) by an acidic group such asa sulfonic group in the molecule. As a counter ion when the salt isformed, a cation such as an alkali metal; ammonia (NH₃); or organicammonium may be mentioned. As specific example of the alkali metal,lithium, sodium and potassium may be mentioned. As specific examples ofthe organic ammonium, alkylamines having 1 to 3 carbon atoms, such asmethylamine and ethylamine; mono-, di- or tri-alkanolamines having 1 to4 carbon atoms, such as monoethanolamine, diethanolamine,triethanolamine, monoisopropanolamine, diisopropanolamine andtriisopropanolamine may be mentioned. Incidentally, M in a case where acompound represented by a general formula (2) which will be describedsubsequently is a salt form may also be selected from theabove-described cations such as the alkali metal; ammonia (NH₃); andorganic ammonium.

As favorable specific examples of the salt of the compound representedby the general formula (1), a salt with an alkali metal such as sodium,potassium or lithium; a salt with a mono-, di- or tri-alkanolaminehaving 1 to 4 carbon atoms, such as monoethanolamine, diethanolamine,triethanolamine, monoisopropanolamine, diisopropanolamine ortriisopropanolamine; and an ammonium (NH₄ ⁺) salt may be mentioned.

When the compound represented by the general formula (1) is a salt form,physical natures of such a compound, such as solubility, and theperformance (in particular, performance as to fastness properties of animage recorded) of an ink containing the salt as a coloring material mayvary in some cases according to the kind of the counter ion of the salt.Therefore, the kind of the salt is favorably selected according to theintended performance of the resulting ink. Incidentally, in order tochange the compound from the free acid form to the salt form, it is onlynecessary to add a material forming such a cation as mentioned above(for example, an alkali metal hydroxide) so as to adjust the pH of aliquid containing the compound into an alkaline range. In order tochange the compound from the salt form to the free acid form, it is onlynecessary to add an acid so as to adjust the pH of a liquid containingthe compound to an acidic range. In addition, in order to change aparticular salt form to another salt form, it is only necessary toconduct ion exchange.

As a more favorable specific example of the coloring material containedin the ink according to the present invention, a compound represented bythe follow general formula (2) may be mentioned.

wherein rings A, B, C and D each indicated by a broken line are,independently of one another, a benzene ring or a nitrogen-containingheteroaromatic ring, the number of the nitrogen-containingheteroaromatic ring is more than 0.0 and 3.0 or less, the remainder isthe benzene ring, M's are, independently of each other, a hydrogen atom,an alkali metal, ammonium or organic ammonium, m is more than 0.0 andless than 3.9, n is 0.1 or more and less than 4.0, and the sum of m andn is 1.0 or more and less than 4.0.

Favorable specific examples of the compound represented by the generalformula (1) are shown in Table 1. Quite naturally, the compoundrepresented by the general formula (1) and used as a coloring materialin the ink according to the present invention is not limited to theexemplified compounds shown in Table 1 so far as such a compound isincluded in the structure of the general formula (1) and the definitionthereof. In addition, as well known by a person skilled in the art, aphthalocyanine type porphyrazine compound such as the compoundrepresented by the general formula (1) is generally present in a stateof a mixture containing a plurality of isomers, and can exhibit theeffect thereof even when used in that state. However, in the presentinvention, a typical one structural formula is described withoutdistinguishing the plurality of the isomers for the sake of convenience.Incidentally, values m and n in Table 1 are expressed by rounding themoff for the purpose of avoiding complication. Therefore, m in Table 1 isexpressed as “0” for the sake of convenience. However, this is a problemof computation process and of course means that m in the general formula(1) is more than 0.0.

TABLE 1 Exemplified compounds of the general formula (1) Exemplifiedcompound A B C D E X R₁ m n 1 3,4-PD Bz Bz Bz EL 2,5-Disulfoanilino Me 21 2 3,4-PD Bz Bz Bz EL 2,4-Disulfoanilino Me 2 1 3 3,4-PD Bz Bz Bz EL2-Sulfoanilino Me 2 1 4 3,4-PD Bz Bz Bz EL 3-Sulfoanilino Me 2 1 53,4-PD Bz Bz Bz EL 4-Sulfoanilino Me 2 1 6 3,4-PD Bz Bz Bz EL2,5-Disulfoanilino Et 2 1 7 3,4-PD Bz Bz Bz EL 2,5-Disulfoanilino i-Pr 21 8 3,4-PD Bz Bz Bz EL 4-Methoxy-2-sulfoanilino Me 2 1 9 3,4-PD Bz Bz BzEL 4-Nitro-2-sulfoanilino Me 2 1 10 3,4-PD Bz Bz Bz EL2-Chloro-5-sulfoanilino Me 2 1 11 3,4-PD Bz 3,4-PD Bz EL3-(Aminocarbonylamino)-5-sulfoanilino Me 1 1 12 Bz 3,4-PD 3,4-PD 3,4-PDEL 2,5-Disulfoanilino Me 0 1 13 Bz 3,4-PD 3,4-PD Bz EL2,5-Disulfoanilino Me 1 1 14 3,4-PD Bz Bz Bz PPL2-Hydroxy-3-acetylamino-5-sulfoanilino Me 2 1 15 3,4-PD Bz 3,4-PD Bz PPL3-Carbonyl-4-hydroxy-5-sulfoanilino Me 1 1 16 3,4-PD Bz 3,4-PD 3,4-PDPPL 3-Methyl-6-methoxy-4-sulfoanilino Me 0 1 17 3,4-PD Bz Bz Bz EL5-Phosphono-2-sulfoanilino Me 2 1 3,4-PD: 3,4-Pyrido (pyridine ringfused at positions 3 and 4) Bz: Benzo EL: Ethylene PPL: Propylene Me:Methyl Et: Ethyl i-Pr: Isopropyl.

The compound represented by the general formula (1) can be synthesizedby, for example, reacting a compound represented by the followinggeneral formula (II) with an organic amine represented by the followinggeneral formula (III) in the presence of ammonia or an ammoniagenerating source. The compound represented by the general formula (II)can be obtained by, for example, chloro-sulfonylating a compoundrepresented by the following general formula (I):

wherein rings A, B, C and D each indicated by a broken line are,independently of one another, a benzene ring or a nitrogen-containingheteroaromatic ring, the number of the nitrogen-containingheteroaromatic ring is more than 0.0 and 3.0 or less, and the remainderis the benzene ring.

wherein rings A, B, C and D have the same meaning as the rings A, B, Cand D in the general formula (I), and n is 1.0 or more and less than4.0.

wherein R₁ is an alkyl group, R₂ is an alkylene group, and X is ananilino group having one or more sulfonic groups, with the proviso thatX may have one or more substituents selected from the group consistingof a carboxy group, a phosphoric group, a hydroxy group, an alkoxygroup, an alkylcarbonylamino group, a ureido group, a nitro group and ahalogen atom.

The compound represented by the general formula (I) can be obtainedaccording to a publicly known process or a process equivalent thereto.As examples of the publicly known process, may be mentioned theprocesses disclosed in International Publication No. 2007/091631,International Publication No. 2007/116933 and International PublicationNo. 2008/111635.

A favorable process for chlorosulfonylating the compound represented bythe general formula (I) includes a process in which the compoundrepresented by the general formula (I) is added to chlorosulfonic acidto conduct a reaction, and a chlorinating agent is then further added toconduct a reaction. When the compound represented by the general formula(I) is reacted with chlorosulfonic acid, a compound in which achlorosulfonyl group and a sulfonic group have been randomly substitutedis obtained, and it is thus difficult to obtain the intended compoundrepresented by the general formula (II) with high selectivity.Therefore, it is favorable that after the compound represented by thegeneral formula (I) is reacted with chlorosulfonic acid, a chlorinatingagent is further added to convert the sulfonic group substituted to achlorosulfonyl group.

When the compound represented by the general formula (I) ischlorosulfonylated, chlorosulfonic acid is used in an amount ofgenerally 3 to 20 times, favorably 5 to 10 times of the mass of thecompound represented by the general formula (I). The reactiontemperature is generally 100° C. to 150° C., favorably 120 to 150° C.The reaction time is generally 1 to 10 hours though it varies accordingto conditions such as the reaction temperature.

Examples of the chlorinating agent include thionyl chloride, sulfurylchloride, phosphorus trichloride, phosphorus pentachloride andphosphorus oxychloride. Among these chlorinating agents, thionylchloride is favorable. The amount of the chlorinating agent added isgenerally 6 to 40 mol, favorably 9 to 20 mol per mol of the compoundrepresented by the general formula (1) though it varies according to thekind thereof. The reaction temperature is generally 30° C. to 100° C.,favorably 50 to 90° C. The reaction time is generally 1 to 10 hoursthough it varies according to conditions such as the reactiontemperature.

The organic amine represented by the general formula (III) can besynthesized according to the following process. First, 5 to 60 mol of acompound represented by “R₁—OH” (a monohydric alcohol), 1 mol of2,4,6-trichloro-S-triazine (cyanul chloride) and 0.8 to 1.2 mol ofsodium hydrogencarbonate are reacted to obtain a reaction liquidcontaining a primary condensate. The reaction temperature is generally 5to 70° C., and the reaction time is generally to 12 hours. Incidentally,the resultant primary condensate is isolated as solids such as wet cakefrom the reaction liquid by a proper method such as salting out, and thethus-obtained primary condensate may also be used to the next reaction.

Then, the resultant reaction liquid containing the primary condensate orthe wet cake (favorably, the reaction liquid) is added to an aqueoussolution of 0.9 to 1.5 mol of aniline having one or more sulfonic groupscorresponding to X. The pH of the reaction liquid is adjusted togenerally 4 to 10 with an alkali metal hydroxide such as sodiumhydroxide to conduct a reaction, thereby obtaining a secondarycondensate. The reaction temperature is generally 5 to 80° C., favorably5 to 40° C., and the reaction time is generally 0.5 to 12 hours.

One mol of the resultant secondary condensate is reacted with 1 to 50mol of a compound represented by “H₂N—R₂—NH₂” (an alkylenediamine),whereby the organic amine represented by the general formula (III) canbe obtained. The pH upon the reaction is generally 4 to 7. The reactiontemperature is generally 5 to 90° C., favorably 40 to 90° C., and thereaction time is generally 0.5 to 8 hours.

An alkali metal hydroxide such as sodium hydroxide or potassiumhydroxide or an alkali metal carbonate such as sodium carbonate orpotassium carbonate may be used for pH adjustment upon the respectivecondensation reactions. Incidentally, the order of the condensationreactions may be suitably determined according to the reactivity of thecompound reacted with cyanul chloride.

The compound represented by the general formula (II) is reacted with theorganic amine represented by the general formula (III) in the presenceof ammonia or an ammonia generating source in, for example, water,whereby the intended compound represented by the general formula (1) canbe obtained. The pH upon the reaction is generally 8 to 10. The reactiontemperature is generally 5 to 70° C., favorably 5 to 40° C., and thereaction time is generally 1 to 20 hours. As ammonia, aqueous ammonia ora water-miscible organic solvent containing ammonia gas may be used. Asspecific examples of a water-soluble organic solvent used in thepreparation of the water-miscible organic solvent containing ammoniagas, dimethylformamide and dimethylacetamide may be mentioned. Theaqueous ammonia or water-miscible organic solvent containing ammonia gasincludes that prepared by a publicly known method such as blowing ofammonia gas into water or a water-soluble organic solvent, or acommercially available product.

As the ammonia generating source, a chemical substance which generatesammonia by neutralization or decomposition may be used. As examples ofsuch a chemical substance, ammonium salts which generate ammonia byneutralization, such as ammonium chloride and ammonium sulfate; andsubstances which generate ammonia by thermal decomposition, such as ureamay be mentioned. Among these, ammonia is favorably used in the form ofaqueous ammonia. In particular, concentrated aqueous ammonia availableas a commercial product (marketed as about 28% by mass aqueous ammonia)or aqueous ammonia obtained by diluting this concentrated aqueousammonia with water as needed is favorably used. Further, the use of theconcentrated aqueous ammonia is favorable because the amount of thereaction liquid can be lessened.

The amount of the organic amine represented by the general formula (III)used is generally about 1 molar equivalent of a theoretical value (thecalculated moles of the organic amine represented by the general formula(III) that are required to obtain the intended value for n in thegeneral formula (1)) with respect to one mole of the compoundrepresented by the general formula (II). However, the amount is suitablyadjusted according to the reactivity of the organic amine and reactionconditions and is generally 1 to 3 molar equivalents, favorably 1 to 2molar equivalents of the theoretical value.

When the compound represented by the general formula (II) is reactedwith the organic amine represented by the general formula (III) inwater, it is theoretically considered that a part of the chlorosulfonylgroup in the general formula (II) is hydrolyzed into a sulfonic group.That is, it is theoretically considered that a compound with a part ofthe “—SO₂NH₂” group in the general formula (1) converted to a sulfonicgroup is mingled in the intended compound represented by the generalformula (1). However, it is generally difficult to distinguish the“—SO₂NH₂” group from the sulfonic group by mass analysis that is one ofgeneral analyzing methods for the phthalocyanine type porphyrazinecompound. From such a reason, in the present specification, otherchlorosulfonyl groups in the general formula (II) than that reacted withthe organic amine represented by the general formula (III) are allexpressed as being converted to the “—SO₂NH₂” group.

Examples of a method for isolating the compound represented by thegeneral formula (1) from the reaction liquid in the final step of theabove-described synthetic process include methods such as aciddeposition (a method of depositing a compound by adding an acid),salting out and acidic salting out to combine them. The salting out isfavorably conducted in an acidic to alkaline range, more favorably in arange of pH 1 to 11. No particular limitation is imposed on thetemperature upon the salting out. However, the reaction liquid is heatedto generally 40 to 80° C., favorably 40 to 60° C. After the heating, forexample, sodium chloride is favorably added to conduct the salting out.A favorable method for isolating the compound represented by the generalformula (1) is such an acidic salting out process that salting out isconducted under very acidic conditions of pH 1.

The phthalocyanine type porphyrazine compound is classified into threekinds of compounds: α-position substitution form, β-positionsubstitution form and α-position and β-position mixed substitution form,according to the substitution position of the substituent. The compoundrepresented by the general formula (1) has a particular number(indicated as an average value) of benzene rings for the rings A, B, Cand D. Therefore, the compound represented by the general formula (1)may also be classified into three kinds of substitution forms accordingto the substitution position of the substituent of the benzene ring likethe phthalocyanine type porphyrazine compound. The compound representedby the general formula (1) may be classified into the α-position andβ-position mixed substitution form.

No particular limitation is imposed on the content (% by mass) of thecompound represented by the general formula (1) in the ink so far as itfalls within a range satisfying reliability as an ink jet ink, such asejection properties. In the present invention, the content (% by mass)of the compound represented by the general formula (1) in the ink isfavorably 0.01% by mass or more and 10.0% by mass or less based on thetotal mass of the ink.

Verification Method of Coloring Material

In order to verify whether the coloring material used in the presentinvention is contained in the ink or not, the following verificationmethods (1) to (3) using high performance liquid chromatography (HPLC)can be applied.

(1) Retention time of a peak(2) Maximum absorption wavelength for the peak in (1)(3) M/Z (posi) and M/Z (nega) of a mass spectrum for the peak in (1)

Alkanediol Having 4 to 6 Carbon Atoms

The ink according to the present invention is required to contains awater-soluble organic solvent including an alkanediol having 4 to 6carbon atoms. If the number of carbon atoms in the alkanediol is 3 orless, the permeability of the ink into a recording medium becomesinsufficient, and so the bronzing resistance of an image recorded is notimproved. If the number of carbon atoms in the alkanediol is 7 or moreon the other hand, the permeability of the ink becomes sufficient, butthere is a possibility that the ink may be thickened or the coloringmaterial may be deposited when water is evaporated, so that the stickingresistance of the ink becomes insufficient. The content (% by mass) ofthe alkanediol having 4 to 6 carbon atoms in the ink is favorably 0.1%by mass or more and 50.0% by mass or less based on the total mass of theink.

As favorable specific examples of the alkanediol having 4 to 6 carbonatoms, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,2-butanediol,1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-pentanediol,1,6-hexanediol and 1,2-hexanediol may be mentioned. Among these,alkanediols having a hydroxy group at both terminals of the alkyl group(main chain) are favorable, and 1,5-pentanediol and 1,6-hexanediol areparticularly favorable. The alkanediols having 4 to 6 carbon atoms maybe used either singly or in any combination thereof.

The content (% by mass) of the alkanediol having 4 to 6 carbon atomsbased on the total mass of the ink is favorably 1.0 time or more and10.0 times or less in terms of mass ratio with respect to the content (%by mass) of the coloring material. That is, “Content (% by mass) ofalkanediol”/“Content (% by mass) of coloring material” is favorably 1.0time or more and 10.0 times or less. If the above-described mass ratiois less than 1.0 time, the permeability of the ink into a recordingmedium becomes insufficient, so that the bronzing resistance of an imagerecorded may not be sufficiently achieved in some cases. If the massratio is more than 10.0 times on the other hand, the viscosity of theink is increased, and the permeability of the ink into the recordingmedium is lowered, so that the bronzing resistance of the image may notbe sufficiently achieved in some cases.

Aqueous Medium

An aqueous solvent that is water or a mixed solvent of water and awater-soluble organic solvent may be used in the ink according to thepresent invention. Deionized water (ion-exchanged water) is favorablyused as the water. The content (% by mass) of water in the ink isfavorably 10.0% by mass or more and 90.0% by mass or less based on thetotal mass of the ink.

No particular limitation is imposed on the water-soluble organic solventso far as the solvent is soluble in water, alcohols, another polyhydricalcohols, polyglycols, glycol ethers, nitrogen-containing polar solventsand sulfur-containing polar solvents may be used. The content (% bymass) of the water-soluble organic solvent in the ink is favorably 5.0%by mass or more and 90.0% by mass or less, more favorably 10.0% by massor more and 50.0% by mass or less, based on the total mass of the ink.Incidentally, the range of the content of the water-soluble organicsolvent is a value including the alkanediol having 4 to 6 carbon atomsand bis(2-hydroxyethyl)sulfone usable as needed. If the content of thewater-soluble organic solvent is below or beyond the above-describedrange, the ejection stability of the resulting ink may not besufficiently achieved at a high level in some cases.

Bis(2-hydroxyethyl)sulfone

Bis(2-hydroxyethyl)sulfone is favorably further contained in the inkaccording to the present invention. Bis(2-hydroxyethyl)sulfone iscontained, whereby the sticking resistance of the ink can be moreimproved. The present inventors presume the reason why such an effect isachieved to be as follows. Bis(2-hydroxyethyl)sulfone has an effect toimprove the solubility of the compound represented by the generalformula (1) in the ink. It is thus considered that when a recording headis left to stand in an environment of high temperature and low humidity(for example, 35° C. in temperature and 15% in relative humidity), inwhich water easily evaporates, deposition of the coloring material inthe neighborhood of an ejection orifice of the recording head isinhibited to more improve the sticking resistance of the ink. Thecontent (% by mass) of bis(2-hydroxyethyl)sulfone in the ink isfavorably 1.0% by mass or more and 10.0% by mass or less based on thetotal mass of the ink.

Other Additives

The ink according to the present invention may contain a water-solubleorganic compound which is solid at ordinary temperature, such as apolyhydric alcohol such as trimethylolpropane or trimethylolethane,urea, or a urea derivative such as ethyleneurea, in addition to theabove-described components as needed. In addition, the ink according tothe present invention may also contain various additives such as asurfactant, a pH adjustor, a rust preventive, a preservative, amildewproofing agent, an antioxidant, an anti-reducing agent, anevaporation accelerator, a chelating agent and a water-soluble polymeras needed.

The ink according to the present invention favorably has proper physicalproperty values because the ink is applied to an ink jet system.Therefore, the surface tension of the ink at 25° C. is favorably 10 mN/mor more and 60 mN/m or less, more favorably 20 mN/m or more and 60 mN/mor less, particularly favorably 30 mN/m or more and 40 mN/m or less. Theviscosity of the ink at 25° C. is favorably 1.0 mPa·s or more and 5.0mPa·s or less, more favorably 1.0 mPa·s or more and 3.0 mPa·s or less.

Other Inks

In order to record a full-color image, the ink according to the presentinvention may be used in combination with other inks having a huedifferent from the ink according to the present invention. As examplesof the other inks, may be mentioned at least one ink selected from thegroup consisting of black, cyan, magenta, yellow, red, green and blueinks. What is called a light color ink having substantially the same hueas such an ink may also be further used in combination. Coloringmaterials used in the other inks and light color ink may be publiclyknown dyes or newly synthesized dyes.

Ink Cartridge

The ink cartridge according to the present invention is provided with anink and an ink storage portion storing this ink. The ink stored in theink storage portion is the above-described ink according to the presentinvention. FIG. 1 is a sectional view schematically illustrating an inkcartridge according to an embodiment of the present invention. Asillustrated in FIG. 1, an ink supply port 12 for supplying an ink to arecording head is provided in a bottom of the ink cartridge. Theinterior of the ink cartridge is the ink storage portion storing theink. The ink storage portion is made up by an ink storage chamber 14 andan absorber storage chamber 16, and these chambers are communicated witheach other through a communication port 18. The absorber storage chamber16 is communicated with the ink supply port 12. A liquid ink 20 isstored in the ink storage chamber 14, and absorbers 22 and 24 holdingthe ink in an impregnated state are stored in the absorber storagechamber 16. The ink storage portion may also be so constructed that thewhole amount of the ink stored is held by the absorber without providingthe ink storage chamber. In addition, the ink storage portion may alsobe so constructed that the whole amount of the ink is stored in a liquidstate without having the absorber. Further, the ink cartridge may alsobe constructed so as to have an ink storage portion and a recordinghead.

Ink Jet Recording Method

The ink jet recording method according to the present invention is amethod of ejecting the above-described ink according to the presentinvention by a recording head of an ink jet system to record an image ona recording medium. Systems for ejecting the ink include a system inwhich mechanical energy is applied to the ink and a system in whichthermal energy is applied to the ink. In the present invention, thesystem in which the thermal energy is applied to the ink to eject theink is particularly favorably adopted. Steps of the ink jet recordingmethod may be those publicly known except that the ink according to thepresent invention is used.

FIGS. 2A and 2B schematically illustrate an exemplary ink jet recordingapparatus used in the ink jet recording method according to the presentinvention, in which FIG. 2A is a perspective view illustrating aprincipal part of the ink jet recording apparatus, and FIG. 2B is aperspective view illustrating a head cartridge. In the ink jet recordingapparatus, a conveyance unit (not illustrated) for conveying a recordingmedium 32 and a carriage shaft 34 are provided. A head cartridge 36 canbe installed on the carriage shaft 34. The head cartridge 36 is providedwith recording heads 38 and 40 and is so constructed that an inkcartridge 42 is set. Inks (not illustrated) are ejected toward therecording medium 32 from the recording heads 38 and 40 while the headcartridge 36 is being carried in a main scanning direction along thecarriage shaft 34. The recording medium 32 is then conveyed in a subscanning direction by the conveyance unit (not illustrated), whereby animage is recorded on the recording medium 32.

EXAMPLES

The present invention will hereinafter be described in more detail bythe following Examples and Comparative Examples. However, the presentinvention is not limited by the following examples unless going beyondthe gist of the present invention. Incidentally, all designations of“part” or “parts” and “%” as to amounts of components described beloware based on mass unless expressly noted.

Synthesis of Coloring Material

Although all compounds obtained by a synthetic process described belowand represented by the general formula (1) are mixtures containing aplurality of isomers, such a mixture containing a plurality of isomersis described as “compound” unless expressly noted. That is, “compound”contains regioisomers of the compound; regioisomers in terms of theposition of the nitrogen atom in the nitrogen-containing heteroaromaticring, isomers in which the ratio (benzene ring)/(nitrogen-containingheteroaromatic ring) as indicated by the rings A, B, C and D in thegeneral formula (1) differs, and α/β regioisomers on the benzene ring ofthe substituted or unsubstituted sulfamoyl group. As described above, itis extremely difficult to isolate a specific compound from a mixture ofthese isomers and determine the structure thereof, and so an exampleamong possible isomers is taken as a representative example for the sakeof convenience, and the structural formula thereof is described. Inaddition, the numbers of the benzene ring and the nitrogen-containingheteroaromatic ring, and the substitution numbers (m, n and the sum of mand n) are each indicated as an average value.

With respect to the compounds obtained according to the syntheticprocess described below, mass analysis, ICP emission spectrometry andabsorbance measurement were conducted to determine the structuresthereof. Incidentally, respective operations such as a reaction andcrystallization were conducted under stirring unless expressly noted. Inaddition, “LEOCOL” used in a synthetic reaction is a surfactant (tradename “LEOCOL TD-90”, product of Lion Corporation). A maximum absorptionwavelength (λ_(max)) is a measured value measured in an aqueous solutionof pH 6 to 9, and an aqueous solution of sodium hydroxide was used forpH adjustment. Incidentally, when a necessary amount of an intendedcompound was not obtained by one run of synthesis, the same operationwas repeated until the necessary amount of the intended compound wasobtained.

Mass Analysis

With respect to the respective compounds synthesized, mass analysis wasconducted under the following conditions.

Ionization method: EI methodMass analyzer: Trade name “SSQ-7000” (manufactured by Thermo Quest Co.,Ltd.)Ion source temperature: 230° C.Degree of vacuum: About 8 mTorr

ICP Emission Spectrometry

With respect to respective compounds containing copper, the content ofcopper was analyzed according to ICP emission spectrometry.Specifically, the analysis was conducted in the following manner. Afterabout 0.1 g of an analytical sample was precisely weighed, and thissample was dissolved in pure water, the resultant solution wasquantified in a 100-ml messflask. After 1 ml of this solution was takento put it in a 50-ml messflask by means of a whole pipette, a fixedamount of Y (yttrium) was further added as an internal standardsubstance. After the volume of the solution was quantified to 50 mL withpure water, the content of copper in the solution was determined by theICP emission spectrometry. Incidentally, an ICP emission spectrometer(trade name “SPS3100”, manufactured by SII Nano Technology Inc.) wasused as the analytical apparatus.

Absorbance Measurement

With respect to the respective compounds synthesized, the absorbance wasmeasured. Measuring conditions of the absorbance are shown below.

Spectrophotometer: Automatic recording spectrophotometer (trade name“U-3300”, manufactured by Hitachi Ltd.)Measuring cell: 1-cm quartz cellSampling interval: 0.1 nmScanning speed: 30 nm/minNumber of measurements: 5 times on the average

Synthesis of Compound A

Synthesis of Compound (a-1)

To 400 parts of sulfolane were added 44.4 parts of phthalic anhydride,16.7 parts of cinchomeronic acid, 144 parts of urea, 13.4 parts ofcopper(II) chloride and 2.0 parts of ammonium molybdate, and theresultant mixture was heated to 200° C. to conduct a reaction for 5hours at the same temperature. After completion of the reaction, theresultant reaction liquid was cooled to 65° C., 80 parts of DMF(N,N-dimethylformamide) was added, and solids deposited were separatedby filtration. The resultant solids were washed with 220 parts of DMF toobtain 112.1 parts of a wet cake. After the resultant wet cake was addedto 340 parts of DMF and heated to 110° C., and stirring was conductedfor 1 hour at the same temperature, solids were separated by filtrationand washed with 300 parts of water to obtain a wet cake. After theresultant wet cake was added to 300 parts of 5% hydrochloric acid andheated to 60° C., and stirring was conducted for 1 hour at the sametemperature, solids were separated by filtration and washed with 300parts of water to obtain a wet cake. After the resultant wet cake wasadded to 300 parts of 5% aqueous ammonia, and the resultant mixture wasstirred for 1 hour at 60° C., solids were separated by filtration andwashed with 300 parts of water to obtain 138.2 parts of a wet cake. Theresultant wet cake was dried at 80° C. to obtain Compound (a-1) as bluesolids.

Synthesis of Compound (a-2)

After Compound (a-1) was gradually added to 46.2 parts of chlorosulfonicacid at room temperature so as not to exceed 60° C., a reaction wasconducted for 4 hours at 140° C. to obtain a reaction liquid. After theresultant reaction liquid was cooled to 70° C., 17.9 parts of thionylchloride was added dropwise over 30 minutes, and a reaction wasconducted additionally for 3 hours at 70° C. After a reaction liquid wascooled to a temperature not higher than 30° C., the reaction liquid wasslowly poured into 800 parts of iced water, solids deposited wereseparated by filtration and washed with 200 parts of cold water toobtain 33.0 parts of a wet cake of Compound (a-2).

Synthesis of Compound (a-3)

To 160 parts of methanol were added 36.8 parts of cyanul chloride, 4parts of LEOCOL and 16.8 parts of sodium hydrogencarbonate, and areaction was conducted for 1 hour at a temperature not higher than 30°C. to obtain a reaction liquid containing a primary condensate. To 280parts of water were added 56.1 parts of 2,5-disulfoaniline and 32 partsof a 25% aqueous solution of sodium hydroxide, thereby adjusting a pH to3 to 5. The reaction liquid containing the primary condensate obtainedin the above-described manner was gradually added to this liquid, and areaction was further conducted overnight while adjusting the pH to 6 to7 with a 25% aqueous solution of sodium hydroxide, thereby obtaining areaction liquid containing a secondary condensate. After 360 parts ofhydrochloric acid and 125 parts of iced water were added to theresultant reaction liquid, and the resultant mixture was cooled to 0°C., 120 parts of ethylenediamine was further added dropwise. A reactionwas conducted for 2.5 hours at 80° C. while adjusting the pH to 5 to 7by adding a 25% aqueous solution of sodium hydroxide to the resultantliquid, thereby obtaining a reaction liquid containing a tertiarycondensate.

The pH was adjusted to 1.0 by adding 55 parts of hydrochloric acid tothe resultant reaction liquid. The amount of the liquid at this time was1,000 parts. To the resultant liquid 200 parts of sodium chloride wasadded, stirring was conducted for 30 minutes, and solids deposited wereseparated by filtration to obtain 183 parts of a wet cake. The resultantwet cake was added to 1,000 parts of water, and the pH was adjusted to9.0 with a 25% aqueous solution of sodium hydroxide to obtain a liquid.The pH was adjusted to 1.0 by adding 55 parts of hydrochloric acid tothe resultant liquid. The amount of the liquid at this time was 1,400parts. To this liquid was added 280 parts of sodium chloride, stirringwas conducted for 30 minutes at room temperature and additionally for 30minutes at 0° C., and solids deposited were separated by filtration toobtain 60 parts of a wet cake. The resultant wet cake was added to amixed liquid of 224 parts of methanol and 56 parts of water to prepare asuspension. After the suspension was stirred for 1 hour at 50° C.,solids were separated by filtration to obtain a 51.3 parts of a wetcake. The resultant wet cake was dried to obtain 37.0 parts of Compound(a-3) as white powder.

Synthesis of Compound A

To 120 parts of iced water 33.0 parts of the wet cake of Compound (a-2)was added, and stirring was conducted for 10 minutes at a temperaturenot higher than 5° C. to obtain a suspension. On the other hand, 2.1parts of the white powder of Compound (a-3) was dissolved in a mixedliquid of 1 part of 28% aqueous ammonia and 40 parts of water to obtaina solution. The resultant solution was added to the above-describedsuspension while keeping at a temperature not higher than 10° C., and areaction was conducted while keeping at pH 9.0 with 28% aqueous ammonia.The resultant reaction liquid was heated to 20° C. while keeping at thesame pH, so as to conduct a reaction additionally for 8 hours at thesame temperature. The amount of the reaction liquid at this time was 225parts. After this reaction liquid was heated to 50° C., 33.8 parts ofsodium chloride was added, and stirring was conducted for 30 minutes,concentrated hydrochloric acid was added to adjust the pH to 1.0 over 20minutes. Solids deposited were separated by filtration and washed with100 parts of a 10% aqueous solution of sodium chloride to obtain 62.3parts of a wet cake. The resultant wet cake was added to 200 parts ofwater, and the pH was adjusted to 9.0 with a 25% aqueous solution ofsodium hydroxide to obtain a liquid. The amount of the liquid at thistime was 275 parts. After this liquid was heated to 50° C., 22.5 partsof sodium chloride was added, and stirring was conducted for 30 minutes,the pH was adjusted to 1.0 over 20 minutes with concentratedhydrochloric acid, and solids deposited were separated by filtration.The solids were washed with 100 parts of a 10% aqueous solution ofsodium chloride to obtain 37.1 parts of a wet cake. The resultant wetcake was added to a mixed liquid of 160 parts of ethanol and 40 parts ofwater to prepare a suspension. After this suspension was stirred for 1hour at 50° C., solids were separated by filtration to obtain a 32.0parts of a wet cake. The resultant wet cake was dried to obtain 10.0parts of Compound A represented by the following formula (A) as bluepowder. The λ_(max) of the resultant Compound A was 605 nm. The numberof the benzene ring in Compound A was 3.0, the number of thenitrogen-containing heteroaromatic ring was 1.0, and m, n and the sum ofm and n fell within respective ranges of 0<m<3.9, 0.1≦n<4.0, and1.0≦m+n<4.0. Taking other analytical results into account, it isconsidered that values of m: about 2.8, n: about 0.2 and m+n: about 3.0are close to the synthesized Compound A (mixture). The resultantCompound A was used in preparation of an ink by converting a counter ionof the acidic groups to a sodium ion with an aqueous solution of sodiumhydroxide.

Synthesis of Compound B

Synthesis of Compound (b-1)

To 220 parts of ethanol were added 36.8 parts of cyanul chloride, 4parts of LEOCOL and 16.8 parts of sodium hydrogencarbonate, and areaction was conducted for 1 hour at a temperature not higher than 30°C. to obtain a reaction liquid containing a primary condensate. To 280parts of water were added 56.1 parts of 2,5-disulfoaniline and 32 partsof a 25% aqueous solution of sodium hydroxide, thereby adjusting the pHto 3 to 5. The reaction liquid containing the primary condensateobtained in the above-described manner was gradually added to thisliquid, and a reaction was further conducted overnight while adjustingthe pH to 6 to 7 with a 25% aqueous solution of sodium hydroxide,thereby obtaining a reaction liquid containing a secondary condensate.After 360 parts of hydrochloric acid and 125 parts of iced water wereadded to the resultant reaction liquid, and the resultant mixture wascooled to 0° C., 120 parts of ethylenediamine was further addeddropwise. A reaction was conducted for 2.5 hours at 80° C. whileadjusting the pH to 5 to 6 by adding a 25% aqueous solution of sodiumhydroxide to the resultant liquid, thereby obtaining a reaction liquidcontaining a tertiary condensate.

The pH was adjusted to 1.0 by adding 55 parts of hydrochloric acid tothe resultant reaction liquid. The amount of the liquid at this time was1,000 parts. To the resultant liquid 200 parts of sodium chloride wasadded, stirring was conducted for 30 minutes, and solids deposited wereseparated by filtration to obtain 183 parts of a wet cake. The resultantwet cake was added to 1,000 parts of water, and the pH was adjusted to9.0 with a 25% aqueous solution of sodium hydroxide to obtain a liquid.The pH was adjusted to 1.0 by adding 55 parts of hydrochloric acid tothe resultant liquid. The amount of the liquid at this time was 1,400parts. To this liquid 280 parts of sodium chloride was added, stirringwas conducted for 30 minutes at room temperature and additionally for 30minutes at 0° C., and solids deposited were separated by filtration toobtain 60 parts of a wet cake. The resultant wet cake was added to amixed liquid of 224 parts of methanol and 56 parts of water to prepare asuspension. After the suspension was stirred for 1 hour at 50° C.,solids were separated by filtration to obtain a 51.3 parts of a wetcake. The resultant wet cake was dried to obtain 37.0 parts of Compound(b-1) as white powder.

Synthesis of Compound B

Ten parts of Compound B represented by the following formula (B) wasobtained as blue powder in the same manner as in the above-describedSynthesis of Compound A except that Compound (a-3) was changed toCompound (b-1). The λ_(max) of the resultant Compound B was 607 nm. Thenumber of the benzene ring in Compound B was 3.0, the number of thenitrogen-containing heteroaromatic ring was 1.0, and m, n and the sum ofm and n fell within respective ranges of 0<m<3.9, 0.1≦n<4.0, and1.0≦m+n<4.0. Taking other analytical results into account, it isconsidered that values of m: about 2.8, n: about 0.2 and m+n: about 3.0are close to the synthesized Compound B (mixture). The resultantCompound B was used in preparation of an ink by converting a counter ionto the acidic groups to a sodium ion with an aqueous solution of sodiumhydroxide.

Synthesis of Compound C

Compound C represented by the following formula (C) was synthesizedaccording to the synthetic process described on page 35 of InternationalPublication No. 2007/091631. When m and n in Compound C are shown asaverage values, m was 2.4, and n was 0.6. This Compound C is acomparative compound of the compound represented by the general formula(1). The resultant Compound C was used in preparation of an ink byconverting a counter ion of the acidic groups to a sodium ion with anaqueous solution of sodium hydroxide.

Synthesis of Compound D

Compound D represented by the following formula (D) was synthesizedaccording to the synthetic process of the compound of the formula (9)described on pages 53 to 54 of International Publication No.2004/087815. In Compound D, m was 2.0 to 3.5, and n was 0.5 to 2.0. ThisCompound D is a comparative compound of the compound represented by thegeneral formula (1). The resultant Compound D was used in preparation ofan ink by converting a counter ion of the acidic groups to a sodium ionwith an aqueous solution of sodium hydroxide.

Preparation of Inks Examples 1 to 12 and Comparative Examples 1 to 9

After the respective components (unit: %) shown in upper parts of Tables2-1 to 2-3 were mixed and sufficiently stirred, the resultant respectivemixtures were filtered under pressure through a filter having a poresize of 0.20 μm, thereby preparing respective inks. Incidentally,“Acetylenol E100” in Tables 2-1 to 2-3 is a trade name of a nonionicsurfactant (product of Kawaken Fine Chemicals Co., Ltd.) In a lower partin each of Tables 2-1 to 2-3, the value (Content (%) of alkanediolhaving 4 to 6 carbon atoms)/(Content (%) of coloring material) was shownas “mass ratio (times)”.

TABLE 2-1 Compositions and characteristics of inks Example 1 2 3 4 5 6Compound A (Na salt) 4.0 4.0 4.0 4.0 4.0 4.0 Compound B (Na salt)Compound C (Na salt) Compound D (Na salt) 1,5-Pentanediol 8.0 3.6 4.040.0 40.4 1,6-Hexanediol 8.0 1,4-Butanediol 3,-Methyl-1,5-pentanediol1,2-Hexanediol 1,3-Propanediol 1,7-Heptanediol 1,2,6-HexanetriolEthylene glycol 10.0 10.0 10.0 10.0 10.0 10.0 Diethylene glycol 10.010.0 10.0 10.0 10.0 10.0 Bis(2-hydroxyethyl) sulfone 5.0 5.0 5.0 5.0 5.05.0 Acetylenol E100 1.0 1.0 1.0 1.0 1.0 1.0 Ion-exchanged water 62.062.0 66.4 66.0 30.0 29.6 Mass ratio (times) 2.0 2.0 0.9 1.0 10.0 10.1

TABLE 2-2 Compositions and characteristics of inks Example 7 8 9 10 1112 Compound A (Na salt) 4.0 4.0 4.0 4.0 Compound B (Na salt) 4.0 4.0Compound C (Na salt) Compound D (Na salt) 1,5-Pentanediol 8.0 8.01,6-Hexanediol 1,4-Butanediol 8.0 40.4 3,-Methyl-1,5-pentanediol 8.01,2-Hexanediol 8.0 1,3-Propanediol 1,7-Heptanediol 1,2,6-HexanetriolEthylene glycol 10.0 10.0 10.0 10.0 10.0 10.0 Diethylene glycol 10.010.0 10.0 10.0 10.0 10.0 Bis(2-hydroxyethyl) sulfone 5.0 5.0 5.0 5.0Acetylenol E100 1.0 1.0 1.0 1.0 1.0 1.0 Ion-exchanged water 62.0 62.062.0 67.0 62.0 34.6 Mass ratio (times) 2.0 2.0 2.0 2.0 2.0 10.1

TABLE 2-3 Compositions and characteristics of inks Comparative Example 12 3 4 5 6 7 8 9 Compound A (Na salt) 4.0 4.0 4.0 4.0 4.0 Compound B (Nasalt) Compound C (Na salt) 4.0 4.0 Compound D (Na salt) 4.0 4.01,5-Pentanediol 8.0 8.0 1,6-Hexanediol 1,4-Butanediol 3,-Methyl-1,5-pentanediol 1,2-Hexanediol 1,3-Propanediol 8.0 1,7-Heptanediol 8.01,2,6-Hexanetriol 8.0 Ethylene glycol 10.0 10.0 10.0 10.0 10.0 10.0 10.010.0 10.0 Diethylene glycol 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0Bis(2-hydroxyethyl) 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 sulfoneAcetylenol E100 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.2 Ion-exchanged water70.0 70.0 62.0 62.0 70.0 62.0 62.0 62.0 69.8 Mass ratio (times) — — — —0.0 0.0 0.0 0.0 0.0

Evaluation

Each of the inks obtained above was charged into an ink cartridge, andthe ink cartridge was installed in an ink jet recording apparatus (tradename “PIXUS Pro 9000 Mark II”, manufactured by Canon Inc.) in which anink is ejected from a recording head by the action of thermal energy. Inthis embodiment, a solid image recorded by applying 22 ng of an ink to aunit region of 1/600 inch× 1/600 inch is defined as “recording duty of100%”. In the present invention, in the evaluation criteria of thefollowing respective evaluation items, C was regarded as an unacceptablelevel, and AA, A and B were regarded as an acceptable level. Evaluationresults are shown in Table 3.

Bronzing Resistance

Solid images of respective gradations with the recording duty changedfrom 10% to 180% in an increment of 10% were recorded on a recordingmedium (trade name “CANON PHOTOGRAPHIC PAPER-GLOSS PRO [PLATINUM GRADE]PT101”, product of Canon Inc.) by means of the above-described ink jetrecording apparatus to obtain a recorded article. A solid image whoserecording duty was 60% in the resulting recorded article was visuallyobserved to make evaluation as to bronzing resistance according to thefollowing evaluation criteria.

AA: No bronzing phenomenon occurredA: Glare from yellow to red tint somewhat occurred according to an angleat which the image was observedB: Glare from yellow to red tint slightly occurredC: Glare from yellow to red tint considerably occurred

Ozone Resistance

Solid images of respective gradations with the recording duty changedfrom 10% to 180% in an increment of 10% were recorded on a recordingmedium (trade name “CANON PHOTOGRAPHIC PAPER-GLOSS PRO [PLATINUM GRADE]PT101”, product of Canon Inc.) by means of the above-described ink jetrecording apparatus to obtain a recorded article. A spectrophotometer(trade name “Spectrolino”, manufactured by Gretag Macbeth Co.) was usedto measure an optical density of a cyan component of the solid image ofeach gradation in the resultant recorded article under conditions of alight source of D50 and a visual field of 2°, thereby specifying a solidimage whose optical density was 1.0. This recorded article was put in anozone fadeometer (trade name “OMS-H”, manufactured by Suga TestInstruments Co.) and exposed to ozone for 20 hours under conditions ofan intrachamber temperature of 40° C., a relative humidity of 55% and anozone gas concentration of ppm. Thereafter, the optical density of thecyan component of the same solid image as specified above was measuredagain. The residual ratio (%) of the optical density was calculatedaccording to ((Optical density after exposure)/(Optical density beforeexposure)×100) to make evaluation as to ozone resistance according tothe following evaluation criteria.

A: The residual ratio of the optical density was 80% or moreB: The residual ratio of the optical density was 70% or more and lessthan 80%C: The residual ratio of the optical density was less than 70%

Sticking Resistance

The above-described ink jet recording apparatus was used to record anozzle check pattern after a recovery operation (cleaning) waspreliminarily conducted. Thereafter, a power cable was pulled out in thecourse where a carriage was operated, whereby a state where a recordinghead is not capped was created. In this state, the ink jet recordingapparatus was left to stand for 14 days under conditions of atemperature of 35° C. and a relative humidity of 15%. Thereafter, thisink jet recording apparatus was left to stand for 6 hours underconditions of a temperature of 25° C. to return the temperature of theapparatus to ordinary temperature. This ink jet recording apparatus wasused to record a nozzle check pattern of PIXUS Pro 9000 Mark II whileconducting a recovery operation, and the resultant nozzle check patternwas visually observed to make evaluation as to sticking resistanceaccording to the following evaluation criteria.

A: The nozzle check pattern could be normally recorded by one to tworecovery operationsB: The nozzle check pattern could be normally recorded by three to fourrecovery operationsC: The nozzle check pattern could not be normally recorded ever afterthe recovery operation was conducted five times or more

TABLE 3 Evaluation results Bronzing Ozone Sticking resistance resistanceresistance Example 1 AA A A 2 AA A A 3 B A A 4 AA A A 5 AA A A 6 B A A 7A A A 8 A A A 9 A A A 10 AA A B 11 AA B A 12 B B B Comparative 1 AA C AExample 2 AA C A 3 AA C A 4 AA C A 5 C A A 6 C A A 7 C A A 8 A A C 9 C AA

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2012-092383, filed Apr. 13, 2012, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An ink comprising a coloring material and awater-soluble organic solvent, wherein; the coloring material comprisesa compound represented by the following general formula (1), and thewater-soluble organic solvent comprises an alkanediol having 4 to 6carbon atoms:

wherein rings A, B, C and D each indicated by a broken line are,independently of one another, a benzene ring or a nitrogen-containingheteroaromatic ring, the number of the nitrogen-containingheteroaromatic ring is more than 0.0 and 3.0 or less, the remainder isthe benzene ring, R₁ is an alkyl group, R₂ is an alkylene group, X is ananilino group having one or more sulfonic groups, with the proviso thatX may have one or more substituents selected from the group consistingof a carboxy group, a phosphoric group, a hydroxy group, an alkoxygroup, an alkylcarbonylamino group, a ureido group, a nitro group and ahalogen atom, m is more than 0.0 and less than 3.9, n is 0.1 or more andless than 4.0, and the sum of m and n is 1.0 or more and less than 4.0.2. The ink according to claim 1, wherein the content (% by mass) of thealkanediol having 4 to 6 carbon atoms based on the total mass of the inkis 1.0 time or more and 10.0 times or less in terms of mass ratio withrespect to the content (% by mass) of the coloring material.
 3. The inkaccording to claim 1, wherein the alkanediol having 4 to 6 carbon atomshas a hydroxy group at both terminals of an alkyl group.
 4. The inkaccording to claim 1, wherein the alkanediol having 4 to 6 carbon atomsis at least one of 1,5-pentanediol and 1,6-hexanediol.
 5. The inkaccording to claim 1, wherein the ink further containsbis(2-hydroxyethyl)sulfone.
 6. The ink according to claim 1, wherein thecoloring material comprises a compound represented by the followinggeneral formula (2):

wherein rings A, B, C and D each indicated by a broken line are,independently of one another, a benzene ring or a nitrogen-containingheteroaromatic ring, the number of the nitrogen-containingheteroaromatic ring is more than 0.0 and 3.0 or less, the remainder isthe benzene ring, M's are, independently of each other, a hydrogen atom,an alkali metal, ammonium or organic ammonium, m is more than 0.0 andless than 3.9, n is 0.1 or more and less than 4.0, and the sum of m andn is 1.0 or more and less than 4.0.
 7. The ink according to claim 1,wherein when the nitrogen-containing heteroaromatic ring is a pyridinering with the position of the nitrogen atom in the pyridine ring asposition 1, fused ring positions of the pyridine ring with theporphyrazine ring in the general formula (1) are positions 2 and 3 orpositions 3 and
 4. 8. An ink cartridge comprising an ink and an inkstorage portion storing the ink, wherein the ink comprises the inkaccording to claim
 1. 9. An ink jet recording method comprising ejectingan ink from a recording head of an ink jet system to record an image ona recording medium, wherein the ink comprises the ink according to claim1.